I. Methodology and technology
The panel display screen, screen visible drive, and key and remote-controlled circuits are integrated. These circuits are to function normally and must ensure that the supply screen visible drive as well as the shared power of key and remote-controlled circuits is normal, the display screen (often vfd screens, lcd liquid crystal screens and led digital screens), the key circuits and their keys are normal, the infrared receivers and their remote-controlled transmission lines are normal, and the main plate is delivered to data (string data), stb (select communication number), clck (hour signal). For those using vfd screens, the lights, around 1 21v, are normal. Table 1 is a common key-controlled circuit (inline screen drive) data, stb, clcsk end-step position. Table 2 is a partial decoded chip ir remote-controlled signal carrier foot position。
1. Discrepancies
The unscreened is often visible as screen-drive circuits, display screen damage, vfd (fluorescent) screens with light wiring voltage, 1 21v fence voltage or low voltage, etc. Also data, stb, clck signals are abnormal or interrupted. If each power supply is measured and checked, and the data, stb, clck signal voltage is also normal (playing or static, data has slight fluctuations around 3. 5 - 3. 7 v, stb around 4. 5 v, clck around 3. 5 v), the screen drive path can be replaced by a screen drive, which is still invalid, and the display screen is damaged。
The display of incomplete pens and multiple dyslexia is typically the display of certain parts of the screen or of the screen-drived circuit or the damage of the inner circuit of some of the driver's feet and the associated welding or welding. The inspection and welding, or the exclusion of the relevant welding factors, are not effective and can be replaced by a screen visible drive circuit, and the display screen is damaged if the replacement is not effective。
2. Operational malfunctions
The main manifestations of operational failure are: remote control is normal but all key controls are invalid or partial keys are invalid; key control is normal but remote control is ineffective; remote control is ineffective at the same time as key controls; remote control is not sensitive, etc。
The remote control is normal but all or part of the key is invalid: one of the reasons for this is that the whole or part of the key is broken. The failure of the key control is usually caused by short-circuit damage to a key, a break in the key-control circuit and the data signal. If you check that all buttons are fine, and the data signal is normal, the key-controlled circuit is bad, so replace it. In the case of broken key function, the disordered function key itself is caused by exposure resistance, so that the new key can be replaced. In operating the circuit, the key is a loss-prone element and replacing the malfunction key is recommended to be replaced in its entirety so as to avoid problems with other keys in the near future。
Key control is normal but remote control is ineffective: it is typically remote control damage, infrared receivers and their remote-controlled transmission lines, etc. The remote control operation cannot be performed under normal conditions, and can measure the normality of the receiving head's power supply end and signal output end voltage, if the signal output end voltage at the receiving head has fluctuated during the operation of the remote control, indicating that the receiving head has received and processed the output of the remotely operated signal, at which time further measurements can be made as to whether the ir remote control signal carrier's foot volt is also able to jump simultaneously to fluctuations, while the non-change indicates that the remote control signal transmission line is not functional and the remote control signal has been delivered; if the signal output end voltage of the receiving head does not fluctuate during the operation of the remote control, the receiving head itself is typically damaged and replacement is sufficient. The ir end, where a remote signal has reached the chip but is not working, is generally the receiving head, where the processing of the post-fishing signal frequency deviates from normal values and cannot be systematically identified and can be replaced by a new receiving head test. If the replacement of the new receiver is still ineffective, the damage to the circuit can be judged as a remote signal within the chip。
Remote control is not effective at the same time as a key control: in some machines, it is common to have a short button circuit in a key-controlled circuit. In remote control and key control operations, there are key priority features, so a short-circuit key is equivalent to a system locking this short-circuit key away from other functional operational instructions, causing failure of both the remote control and the key control. There is, of course, the possibility of both remote and key-controlled circuit failure, although the odds are still relatively small。
Remote control is insensitive: when the remote control is normal, it is sometimes effective and sometimes ineffective, or the distance and angle of the remote control to the disc is constantly altered to enable it to operate, usually with poor reception head. However, power filtering causes disturbance of the receiver and the system, leading to remote insensitive malfunctions, which are more common in routine maintenance. In case of such failure, it is advisable to first check, replace, and replace the filtering capacitor attached to the receiving head source foot, as well as whether the primary filtering caps of the switch power, which, if normal, can replace the receiver, become smaller or non-capable. It is worth mentioning that when the main filter of the switch's power is damaged, the top or tipping is generally deformed or there is a leak, but there is also a partial loss of capacity that has a good appearance and must be removed for testing to ensure that no error is made。
By the way, if you apply touchscreen control to the panel, when one of its functions is short-circuited, there is a failure that cannot be controlled by key or that the key control and remote control fail simultaneously. Since this touch screen control board is integrated, it is difficult to deal with it separately, preferably new. If there are no fittings, the emergency response can lead to the removal of the leg from the circuits associated with the presence of short circuits on the touch screen control panel, so that the rest of the key is returned to normal use, except for the failure of the short circuit key。
Examples of inspections
A han sound 8200t is unscreened and is ineffective。
The screen visible drive is associated with the use of sm1628 on the key-control matrix circuit, along with the failure of the screenless and key-controlled circuit because it is associated with the sm1628 itself and its power supply or the data, stb, clck signals。
First, the sm1628 power supply seven foot voltage is normal, then the data, stb, clck signals are normal, and it turns out that the sm1628 clck transmitter three foot voltage is abnormal only around iv. After further examination, the clck welds connected to the main panel have been welded and other welds have been welded to varying degrees, and their rewelding has been eliminated。
A han sound 8200t without screens. The key control and remote control are normal, indicating that the power supply and the data, stb, clck signals are generally normal and that the failure without screen should be either sm1628 itself or the display screen。
After this case was replaced by sm 1628, it became normal。
A han sound 8200t display screen displays incomplete pens。
The sm1628 is used for the sm1628 screen drive and key matrix circuit, and the led digital screen is visible。
The display screen is shown to indicate that the power supply of sm1628 and the data, stb, clck signals are generally normal because of the flex welding of the sm1628 or sm1628 or the zulu d digital screen, and damage to the internal related port circuit。
Checking and welding the above-mentioned associated tripods is ineffective, and the sm1628 failure remains, indicating that the malfunction is on the screen. Replaces the same-specified d-digital screen with a normal screen display。
One of the oca 308b sets shows up occasionally。
The screens are sporadic and the problem should be caused by poor circuit contact at the casket。
The screen displays a d-digital screen compared to sc6928b on the visible drive-key matrix circuit. Test-drive panel lines connected to the main panel have no effect on failure. The pressure panel, with frequent failures, indicates poor exposure on the panel, especially when pressing sc6928b. Look closely at the lead feet of sc6928b and the copper bolts in its vicinity, and find that there's a bad spot on the line to sc6928b + sv, and after cleaning them up, there's a broken copper bolt at the point. Once the broken copper blade is welded, the failure does not occur。
An ace digital dv-3088 type key control and remote control are not working。
After testing, the remote control is normal and the problem should be inside the machine。
Opens the shell, detects that the remote receiver + 5v is powered, and the signal output foot jumps at the remote control, indicating that the remote receiver is basically normal. Considering that key controls are also ineffective, the root causes are considered to be key-controlled circuits, since when key-controlled circuits are especially short-circuited, operational controls are locked into the functional state of the short-circuited key, where other key controls, as well as remote-controlled signals, are not acceptable to the cpu system, resulting in the failure of key controls and remote controls. After checking the key buttons on the opposite panel, it was found that the barrier between the play/suspensive buttons is only around in, indicating the short-circuit damage, and that the key and remote control are back to normal after using a new microswitch。
An ace digital 3088ad remote control operation is insensitive and sometimes remote。
During the test, it was found that the key control was normal, remote control was insensitive and sometimes remote, and that the image was shown in a more serious way。
Measuring the power supply of the remote-controlled receiver is normal, the voltage of the signal output end is normal when operating the remote control, while the ir remote-controlled signal transmission links from the head-out end to the main plate are well connected and suspect that the receiving head is not functioning well. The replacement of the new header malfunction remains valid, indicating other causes of the malfunction. Finally, the main filter cap c8 (47 m f/ 400v) which is the power of the switch is disabled, replaced by a replacement, the remote control operation is restored and the image of the marseek phenomenon disappears。
A 711-type 710 machine key is normal but not remotely operated。
The power supply of the remote control receiver + 5v is normal, with a signal output end voltage of around 4. 5v, but the output end voltage does not fluctuate when the remote control is operated, whereas the remote control itself is normal and the receiver is judged to have been damaged。
When the new header is replaced, the remote control operation returns to normal。
A high-tech key is normal, but remote control requires close operation to be effective。
The tester found that the remote control operation was effective within 20 cm from the front of the remote receiver window, and that it was not effective beyond that distance。
The analysis concluded that the reason for the short remote distance was, first, the lack of electricity in the remote control battery, the reduced capability of the infrared launch tube, and, second, the reduced reception capacity of the receiving head, the receipt of window grinding or remote signal penetration with a dirty impact。
The remote control is verified by means of a remote control detector. The receiving window was checked for lack of grinding and contamination, the panel was removed and the receiving head was operated directly with a remote control, which failed in the same way. The remote control is operated at a distance of 20 cm at this time to measure that the signal output end voltage of the receiving head is virtually non-floating, but within 20 cm it is normal and indicates poor performance of the receiving head. When the receiver is replaced, the remote distance reaches around 8m and the failure is eliminated。
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